微波辐射条件下季戊四醇双缩醛和双缩酮化合物的合成

微波辐射硫酸锆-硅胶催化季戊四醇与醛、酮缩合反应,高收率制得了双缩醛和双缩酮化合物.该方法操作简便,收率高,催化剂可重复使用,是一种环境友好型催化反应.     

An Efficient and Practical Procedure for Synthesis of Diacetals

Pentaerythritol diacetals are useful in many fields. They can be applied as plasticizers and vulcanizers of various polymeric materials, as raw materials for production of valuable resins and lacquers, as physiologically active substances and as defoamers for washing solution containing anionic surfactants. [ 1 ～ 4] Synthsis of diacetals from 2,2bis(hydroxymethyl)-1, 3-propanediol with aldehydes and ketones in refluxing toluene using ZrO2/S2O2- 8 solid superacid as catalyst in 85% ～ 99% yields has been described. The catalysts are easily regenerated by washing with ethanol followed by drying at 120 ℃ for 4 h and could be reused 5 times for the synthesis pentaerythritol diacetal 3e without significant loss of activity. This method possesses the advantages of the operational simplicity, short reaction time, use of inexpensive materials, non-corrosion, non-polluting, high yields and reusable catalysts.     

2,4,4,6-Tetrabromo-2,5-cyclohexadienone (TABCO), N-Bromosuccinimide (NBS) and Bromine as Efficient Catalysts for Dithioacetalization and Oxathioacetalization of Carbonyl Compounds and Transdithioacetalization Reactions

The use of 2,4,4,6-tetrabromo-2,5-cyclohexadienone (TABCO), N-bromosuccinimide (NBS), and bromine as efficient catalysts for conversion of carbonyl compounds to their cyclic and acyclic dithioacetals and 1,3-oxathiolanes under mild reaction conditions are described. These catalysts are also used for efficient transdithioacetalization of acetals, diacetals, ketals, acylals, enamines, hydrazones, and oximes with high yields in the presence of thiols.     

Synthesis of dialdehydes of tetrahydrofuran series

Summary The hydrogenation of the diacetals of furan dialdehydes gave the previously unknown diacetals of tetrahydrofuran dialdehydes, which by hydrolysis were converted to the previously unknown dialdehydes of the tetrahydrofuran series.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 380–381, February, 1965     

Synthesis of cyclic diacetals of fumaraldehyde, α, α'-dibromosuccinaldehyde,and but-2-ynedial

A number of cyclic diacetals of but-2-ynedial, fumaraldehyde, andα, α'-dibromosuccinaldehyde have been synthesized by the transacetalation of bis(dimethyl acetal)s of 1,2- and 1,3-glycols. The succinaldehyde derivatives have also been obtained by the bromination of the corresponding diacetals of fumaraldehyde.     

Acetalization of Carbonyl Compounds as Pentaerythritol Diacetals and Diketals in the Presence of Cellulose Sulfuric Acid as an Efficient,Biodegradable and Reusable Catalyst

This paper reports a practical and green method for the acetalization of carbonyl compounds as pentaerythritol diacetals and diketals derivatives using cellulose sulfuric acid as a biodegradable and reusable solid acid catalyst under thermal solvent‐free conditions.     

New Applications of Solid Silica Chloride (SiO 2 -Cl) in Organic Synthesis. Efficient Preparation of Diacetals of 2,2-Bis(Hydroxymethyl)-1,3-propanediol from Different Substrates and Their Transthioacetalization Reactions. Efficient Regeneration of Carbonyl Compounds from Acetals and Acylals

A new application of solid silica chloride, an easily available and efficient catalyst for the preparation of diacetal of 2,2-bis-(hydroxymethyl)-1,3-propanediol from aldehydes, acetals, acylals, and oximes, is described. Transthioacetalization of diacetals of 2,2-bis-(hydroxymethyl)-1,3-propanediol into their corresponding 1,3-dithianes and 1,3-dithiolanes in the presence of silica chloride is presented. Efficient regeneration of carbonyl compounds from their corresponding acetals, ketals, diacetals, and acylals in the presence of this catalyst also is described.     

MICROWAVE-ASSISTED ACETALIZATION OF PENTAERYTHRITOL CATALYZED BY 12-TUNGSTOPHOSPHORIC ACID

Efficient conversion of carbonyl compounds and pentaerythritol to corresponding diacetals in the presence of 12-tungstophosphoric acid under microwave irradiation is described.     

Chemistry of acetals

Summary Optimum conditions were developed for the preparation of 3-ethoxyacrolein, 3,3-diethoxypropionaldehyde, and 3,3-diethoxy~2-methylpropionaldehyde by the hydrolysis of the diacetals of malonaldehyde and methylmalonal dehyde in presence of p-toluenesulfonic acid and phosphoric acid.     

微波促进活性炭负载磷钨酸催化合成短链季戊四醇双缩醛

以活性炭负载磷钨酸为催化剂,用微波辐射法合成了5种短链季戊四醇双缩醛(3a~3 e),其中季戊四醇双缩丙醛(3b)未见文献报道。3的结构经1H NMR,IR和元素分析表征。     

微波辐射条件下季戊四醇杂二缩醛(酮)的合成

在微波辐射下, 以活性炭负载磷钨酸为催化剂, N,N-二甲基甲酰胺为溶剂, 将季戊四醇与醛(酮)缩合得到季戊四醇单缩醛(酮), 然后再与另一种醛缩合合成了9种季戊四醇杂二缩醛(酮). 产物经过元素分析, IR和¹H NMR表征.     

Dietylpentaerythritol diacetals in the synthesis of phosphorus containing macroheterocycles

Synthesis of phosphorus-containing macroheterocycles based on the symmetrical dipentaerytritol diacetals and trivalent phosphorus reagent is studied. Effective peracetalization of dimethoxymethane with dipentaerytritol is performed.     

A new approach to the synthesis of diacetals（diketals） pentaerythritol catalyzed by SO3H-functionalized ionic liquids

<正>In this article,an efficient,simple and environmentally friendly approach to the synthesis of diacetals(diketals) pentaerythritol using SO_3H-functionalized ionic liquids(ILs) as catalysts was reported.The ILs show high catalytic activity and reusability with good to excellent yields of the desired products.Hammett method has been used to determine the acidity order of these ionic liquids and the results are consistent with the catalytic activities observed in acetalization reaction.Maximum product yield of 93%was observed on using[PSPy][OTf]as catalyst and it can be reused at least 8 times without obvious activity loss.     

Trichloroisocyanuric Acid,as an Industrial Chemical,Promotes Transthioacetalization of Diacetals of 2,2-Bis (Hydroxymethyl)-1,3-propanediol and Cleavage of Thioacetals

Trichloroisocyanuric acid has been used as a mild, efficient, and new catalyst for transthioacetalization of diacetals of 2,2-bis (hydroxymethyl)-1,3-propanediol in CH 2 Cl 2 at room temperature. A clean, easy, and general method for efficient deprotection of thioacetals to their corresponding carbonyl compounds using trichloroisocyanuric acid/silica gel and water system also is described.     

Stereochemistry of bisdioxolane systems

A number of diastereomers of cyclic diacetals of succinaldehyde were obtained by transacetalation of succinaldehyde bis(dimethylacetal) with the optical antipodes of tosylglycerol. The configurations of the products were determined.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1608–1610, December, 1973.     

Stereochemistry of didioxolanyl systems

Diastereomeric cyclic mono- and diacetals of p-phthalaldehyde, 2,5-diformylfuran, and 2,5-diformylthiophene were synthesized under conditions of thermodynamic and kinetic control. The ratios of the diastereomers and their configurations were determined by PMR spectroscopy.See [1] for communication I.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1330–1333, October, 1976.     

Comparative reactivity of diacetals of the type (C2H5O)2CH(CH2)nCH(OC2H5)2

Summary The reactivity of diacetals in the reaction with vinyl ether in comparison with the diacetal of malonic dialdehyde increases in the following order: diacetal of glyoxal < malonic diacetal < succinic diacetal < glutaric diacetal < adipic diacetal.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 1657–1658, September, 1965     

微波辐射活性炭负载磷钨酸催化合成季戊四醇双缩酮(醛)

在微波辐射下，以活性炭负载磷钨酸为催化剂，不用溶剂，合成了8种季戊四醇双缩酮（醛），以环己酮与季戊四缩的缩合为模型反应进行优化，其优化反应条件为：季戊四醇2．0g，催化剂0．3g，环己酮4．0mL，微波输出功率600W，辐射时间3min，产率达95．4％，该条件下的反应速度是常规加热反应速度的30倍，所得产物经元素分析，IR和1H NMR表征。     

Synthesis of Diacetals of 2,2-bis(Hydroxymethyl)-1,3-Propanediol Under Microwave Irradiation

Nine diacetals (3a-i) of 2,2-bis(hydroxymethyl)-1,3-propanediol (2) were prepared by condensation of aldehydes with 2 under microwave irradiation in the presence of TsOH without solvent.     

New syntheses of unsymmetrical thiepins and their selenium analogues

New routes toward fused thiepins and their selenium analogues are described, wherein initial cleavage of suitable diaryl disulfides or selenides bearing masked aldehyde functionalities with an N-protected and metalated indole-3-carbaldehyde acetal or a lithiated 2-bromobenzaldehyde acetal derivative gave a set of unsymmetrical diacetals. Subsequent deacetalization, followed by McMurry coupling, afforded the target unsymmetrical thiepins and selenepins.